In a nutshell
This study investigated whether reducing blood pressure too much in patients with cardiovascular disease puts them at risk of developing heart problems.
Some background
High blood pressure occurs when pressure inside blood vessels is too high. Cardiovascular disease refers to when arteries become narrowed due to a build up of cholesterol or fat.
High blood pressure and cardiovascular disease causes the heart to work harder in order to push blood against high pressure and through narrowed arteries. This can cause the walls of the heart to thicken, especially the main pumping chamber of the heart, the left ventricle, called left ventricular hypertrophy. Left ventricular hypertrophy can result in a major heart event such as heart failure or heart attack.
However, it is feared that reducing blood pressure too much might be dangerous for patients with cardiovascular disease.
Methods & findings
The study investigated whether reducing blood pressure in patients with cardiovascular disease puts them at risk of having a major heart event, comparing to patients without cardiovascular disease.
A total of 1,111 patients with high blood pressure were included in the study, 216 of which had cardiovascular disease. Blood pressure was measured in millimeters of mercury (mmHg). For blood pressure readings two numbers are shown – the top number which measures the pressure in the arteries when the heart is beating (systolic blood pressure: SBP) and the bottom number which measures the pressure when the heart is relaxing or filling (diastolic blood pressure: DBP). Blood pressure is considered normal at around 120/80 mmHg.
Patients in the study had a SBP >150 mmHg. They were randomonly assigned a blood pressure target of either <140 mmHg (standard treatment) or <130 mmHg (tight treatment), where <130 mmHg represented patients that had their blood pressure reduced more.
In patients with cardiovascular disease, it was found that after 2 years, the occurrence of left ventricular hypertrophy occurred less frequently in the group that had a blood pressure target of <130 mmHg (14% of patients), compared to patients that had a blood pressure target of <140 mmHg (24%).
Additionally, it was found that the occurrence of heart events, such as heart attack, and death were lower in the <130 mmHg group than in the <140 mmHg group.
When comparing patients with and without cardiovascular disease, tightly controlled blood pressure <130 mmHg reduced the risk of heart events to a similar extent in both groups.
The bottom line
The study concluded that treatment aimed at lowering SBP <130 mmHg reduced the occurrence of heart events, death and left ventricular hypertrophy in patients with hypertension regardless of having cardiovascular disease or not. Therefore, reaching a SBP blood pressure target <130 mmHg is safe and not dangerous for patients with cardiovascular disease.
The fine print
It has been suggested that while a blood pressure target of <130 mmHg is safe, blood pressure that is below the normal range e.g. a SBP <110 mmHg, is considered to be dangerous for patients with cardiovascular disease. Also, the study did not take into account diastolic blood pressure and what effects it has on cardiovascular heath.
What’s next?
If you or someone you know has high blood pressure and cardiovascular disease, talk to a doctor about what your target blood pressure should be.
Published By :
Hypertension
Date :
Dec 16, 2013
